Plants Furnish Society with More Than Food




  • Plants provided early societies with shelter, clothing and fuel
    • humans have used biomass energy from plants (as fuels) for millenia


  • Modern civilizations: plants provide various media for written communications


  • Future civilizations: Are plant based products to answer to some of societies biggest problems
    • bioplastics?

The Most Vintage Crafts: Basket Weaving


  • Basketry present in every human culture
    • tough to date, because perishable
    • Egyption baskest = 10,000 years old
    • predates pottery!!!


  • Early humans may have used bird’s nests


  • Basket making does cross gender barriers
    • Pomo tribe in California


  • Plants used for baskets region dependent
    • palm and coconut in tropics
    • tree parts in temperate regions
    • grasses in prairies

Plant Fibers


  • Fiber: long tapering plant cells with cellulose
    • ground tissues: sclerenchyma cells
    • thick cells walls
    • lignin, tannin, pectin


  • Most valuable fibers are mostly cellulose and white
    • cellulose has tensile strength of steel


  • Commercial fibers are elongate masses of plant material
    • not individual cells
    • limited # of plant species


  • Provide cloth, rope, paper, etc for millennia
    • rope from flax 30,000 years ago

RSW1 Gene Breakthrough





  • RSW1 gene codes for the enzyme responsible for cellulose production
    • cellulose synthase


  • Isolated in Arabidopsis and cotton


  • Can scientists manipulate cellulose content of plants used for fibers?

Fiber Types


  • Natural fibers are plant or animals based
    • synthetics may still use natural sources
    • rayon still has cellulose from wood pulp


  • Classified according to use:
  1. textile fibers: used to weave cloth
  2. cordage fibers: used to make rope
  3. filling fibers: used to stuff things


  • Classified from source on plant:
  1. surface fibers: coverings of leaf, fruit, seeds
  2. soft fibers: clusters of phloem fibers
  3. hard/leaf fibers: veins of leaves

Extracting fibers and Spinning Yarn



  • Surface fibers separated from plants mechanically
    • ginning

Extracting Fibers and Spinning Yarn



  • Surface fibers separated from plants mechanically
    • ginning


  • Soft fibers extracted using microbial degradation
    • retting, removes soft tissues


  • Hard fibers scraped away by hand or machine
    • decortication


  • First spinning wheel in India ~750 a.d
    • big advancements during industrial revolution

King Cotton



  • Rendering cotton into cloth was discovered independently in new & old worlds


  • Harvested from wild plant in coastal Peru 10,000 years ago
    • domesticated 4,500 years ago


  • Cotton cloths dates 5,000 years in India
    • spread to Babylonia
    • Arabs brought cotton to Spain


  • Cotton brought to Florida in 1556
    • commercial crop from southern colonies

Cotton Plant



  • 20-30 species in the genus (Gossypium)
    • native to Asia, Africa, Americas and Australia
    • shrub with palmate leaves
    • warm climate with lots of water


  • Currently the most popular natural fiber
    • 50% of world’ textiles


  • Fruit of cotton is a capsule, splits along 5 seams
    • fibers are hairs that extend from seed coats (10)
    • 20,000 hairs per seed
    • hairs naturally twisted

Bioengineered Cotton


  • Bollgard = Bt cotton created by Monsanto
    • effective against many cotton pests
    • bollworms and budworms
    • one of most planted transgenic crops


  • Bt cotton yield gain +10% in USA
    • large reductions in insecticide use


  • Bollworm pests damage higher in India
    • small farms cannot afford insecticides
    • yields increase 60% with Bt


  • Transgenic research combines cotton & polyester
    • feel of cotton + heat retention
    • ‘natural’ cotton-poly blend

Linen: An Ancient Fabric


  • Flax (genus Linus) delicate, long, slender stems
    • fibers from phloem cells


  • May be oldest plant fiber used to make cloth
    • 30,000 year old wild flax fibers in cave used during stone age
    • used to bind tools or weave baskets?
    • fibers appear to have been dyed!


  • Ancient Egypt was the ‘land of linen’
    • worn by royalty or in mummy cloths
    • exported for use in sails


  • Grown in Soviet Union, China and Western Europe

Plant Fibers Vary by Region and Culture


Wood and Wood Products


  • Ranks next to food in importance to human society
    • construction, fuel, synthetics
    • strength & insulating properties (construction)


  • 1/3 of land surfaces covered by forests
    • 7.5 million hectares removed a year
    • long history: humans w/ fire


  • Usage rate exceeds regeneration
    • most forests unmanaged


  • Forest removal greater for agriculture than for timber
    • or fuel

Billion to Trillion Tree Campaigns


Hardwoods vs Softwoods



  • Wood is secondary xylem (vascular cambium)
    • lots of strong (cellulose) dead cells


  • Wood strength determined by cell wall thickness, types of xylem cells & fibers


  • Hardwood lumber = angiosperm trees
  • Softwood lumber = gymnosperm trees (conifers)


  • Generally angiosperm lumber is more dense

Wood for Fuel



  • Chief source of fuel until recent times


  • Developing nations still depend on wood for fuel
    • 2 billion people use for heating/cooking
    • prominent in the tropics


  • Charcoal production originated 7,000 years ago
    • partial combustion with low air flow
    • burns at higher temperatures
    • caused the decimation of European forests

Pulp and Paper


  • Wood pulp = watery suspension of pulverized wood
    • mostly xylem cells and fibers
    • ~50% of harvested wood goes to pulp
    • processing removes lignin (brown color)


  • Traditional processing (chlorine) harmful to environment
    • utilization of wood-rotting fungi
    • transgenic Eucalyptus w/ low lignin


  • Wood pulp used for paper, cardboard and cellophane


  • Each American uses 700 lbs of paper
    • despite the internet
    • 1 billion trees harvested a year

The Future of Paper: Hemp? Again?